1. Field of the Invention
The present invention relates to a correction stick of solid type for making corrections of mistakes in writing.
2. Prior Art
Correction fluids, that is, correction materials of solution type have been used for making corrections of mistakes in writing or mistyping, however, there have been experienced some drawbacks such as (1) applicator such as brushes being required, (2) dispersed pigments being liable to settle out when correction fluids being left to stand for a considerable time, (3) correction fluids being thickened gradually by volatility loss of solvent in a reservoir and spreadability getting worse, (4) fluids being spilled when a reservoir falls down and (5) consecutive use being limited when correction fluids being applied with brushes.
The above mentioned drawbacks may be solved by using a correction stick. Heretofore, there have been made some proposals for providing a correction stick but commercial production has not been made, because it was difficult to obtain a correction stick having good properties in hardness, spreadability and opacifying effect. Said difficulty was caused by a gelatinizer.
For example, Japanese patent applications laid open under No. 51-10652 and No. 58-162674 employed benzalsorbitol as a gelatinizer. When said gelatinizer is used in an amount to form a gel having a practical hardness (fracture strength 3,500-6,000 g), a correction material is hardly transferred on a paper product. As a result, the opacifying effect is low. On the contrary, when the amount of said gelatinizer is reduced to obtain practical opacifying effect, practical hardness can not be obtained. Said gelatinizer is not preferred from the view point of safety and sanitation. Further a heat-sensitive paper product is subjected to shade change. Oil ink is apt to run.
Alkali metal salts or ammonium salts of aliphatic carboxylic acids having carbon atoms of 8 to 36 may be used as a gelatinizer, however, when said gelatinizer is used in an amount to obtain a practical hardness, a correction material obtained is easy to slip on a paper product so that good spreadability with moderate friction is not obtained. Besides transfer on a paper product is reduced and the opacifying effect is weak. In addition, the viscosity of composition for correction material becomes too high to be filled in a container. Said gelatinizer having dispersion properties, the strength of dry film formed with correction material is too weak to write thereon. Oil ink runs occasionally. On the contrary, when the amount of said gelatinizer is reduced, a practical hardness can not be obtained.
Japanese patent publication No. 56-34193 made a proposal to use wax as a gelatiner. But the use of wax affects uniform spreadability. Runaway occurs on an aqueous ink. The strength of dry film is too weak to write thereon.